| Country: | Northern Territory |
| Type: | parliamentary |
| Ongoing: | no |
| Election Date: | 4 October 2003 |
| Party1: | Country Liberal Party |
| Popular Vote1: | 1,231 |
| Percentage1: | 41.9% |
| Swing1: | 10.3 |
| Candidate2: | Sharon Hillen |
| Party2: | Australian Labor Party (Northern Territory Branch) |
| Popular Vote2: | 955 |
| Percentage2: | 32.5% |
| Swing2: | 6.5 |
| Candidate3: | Jim Forscutt |
| Party3: | Independent politician |
| Popular Vote3: | 524 |
| Percentage3: | 17.8% |
| Swing3: | 17.8 |
| 2Blank: | TPP swing |
| 1Data1: | 54.3% |
| 2Data1: | 10.2 |
| 1Data2: | 45.7 |
| 2Data2: | 10.2 |
| MP | |
| Before Party: | Country Liberal Party |
| After Party: | Country Liberal Party |
A by-election for the seat of Katherine in the Northern Territory Legislative Assembly was held on 4 October 2003. The by-election was triggered by the resignation of Country Liberal Party (CLP) member Mike Reed, a former Deputy Chief Minister. The seat had been held by Reed since its creation in 1987.
The CLP selected Fay Miller, the owner of Red Gum Tourist Park, as its candidate. The Labor candidate was Sharon Hillen, while three independent candidates contested, including the mayor of Katherine, Jim Forscutt.